Primaeval Man in the Valley of the Lea. 109
America, and northwards towards Iceland. At this period of
time Clapton and Homerton on one side and Leyton and
Stratford on the other were the points where the Lea poured
itself into the Thames. The great width of the stream in
Palaeolithic times is proved by the presence of the gravel-
terraces ; that these terraces were really the old river-margins
(now sometimes a mile or even four miles from the stream)
is proved by the abundance of fossil shells of land and fresh-
water molluscs contained in them.
In fig. 1 I have engraved a small portion of North-east
London, including Tottenham, Stamford Hill, Walthamstow,
Woodford, Snaresbrook, and Barking Side. The clotted
portion shows the disposition of the gravels, and their
positions in regard to the Lea and Roding. No doubt the
gravel banks were at one time continuous, and so prevented
the river from overflowing the country, but centuries of
denudation have now removed part of the gravel. The Plan
is engraved to a scale of one inch to a mile, and at fig. 2 is a
section of the ground to the same scale; the vertical scale
being 800 feet to one inch. The solid black portions on the
tops of the elevations show the implement-bearing gravels,
and the black below the sea-level line is the gravel beneath
the Lea and Roding. The figures indicate the heights above
the Ordnance datum or mean sea-level. b represents the
London-clay on which the gravels rest; o, the Woolwich and
Reading beds; d, Thanet sand; b, Chalk; f, Upper Green
sand; g, Gault. Beneath the general section are two other
sections,—figs. 3 and 4, through the rivers Lea and Boding,
—showing the gravels contiguous to and under the streams.
These are drawn to a horizontal scale of three inches to the
mile, and a vertical scale of 320 feet to an inch, to more
clearly show the gravels as they rest on the London-clay.
The plan and sections are founded, by permission of Mr.
William Whitaker, on the admirable geological Model of
London in the Museum of Practical Geology in Jermyn Street.
The enormous power of the ancient Lea and Thames during
flood-times is proved by the huge masses of sandstone fre-
quently met with in the gravel. I measured a block last